1. Field of the Invention
This invention relates to compression-operated liquid extraction devices and, more particularly, to an extraction device having elongated drainage openings.
2. Description of Related Art
Batch process, compression-driven liquid extraction devices have been well known for many years. Existing devices compress wet waste in a compression chamber below a loading hopper. A hydraulic ram provides pressure to the wet waste. Drainage holes or grates in the sides of the compression chamber permit liquid to escape from the wet waste. Typically, the liquid is extracted directly under the loading hopper. A few designs provide a short extension of the compression chamber past the loading hopper to improve the liquid extraction efficiency. A door on the exit of the chamber is sometimes used to increase the back pressure and obtain a higher degree of compression.
The existing designs generally provide inadequate or incomplete moisture extraction for some important purposes. For example, the moisture content of paper pulp waste, after being processed through existing compression-driven extracting devices, typically exceeds 65% which is not acceptable for many landfills or incinerators. In addition, liquid in the remaining mass is largely unevenly distributed; there is more liquid remaining in the top and bottom of the mass than at the sides. With existing devices, liquid from inside the mass of wet waste must take a longer path to reach a drainage exit. To compensate, the grate design of existing devices provides additional area for drainage but allows a higher percentage of solids to escape with the liquid and also clog the grates. In addition, the grate design of existing devices is unsuitable for high-pressure service.